What do you want to do on your 80th birthday? Gaze out on to the silvery surf unrolling behind your cruise liner? Gather your nearest and dearest for cake and carpet slippers? Give thanks that you're still here?

Philip Roth, who becomes an octogenarian on Tuesday, doesn't seem the most obvious candidate for the traditional leisure pursuits of the affluent retired, but in any case he's got somewhere else to be on the night in question, namely, the Billy Johnson Auditorium of the Newark Museum, New Jersey, where a champagne reception will mark the conclusion of the Roth@80 Conference.

Such luminaries as Edna O'Brien, Jonathan Lethem and Hermione Lee will be in attendance; a bus tour will whisk delegates around the choicest Roth-related sights; and sessions including Yeatsian Agony in Late Roth and Newark: The Shtetl will no doubt provoke intense debate. One might almost wish for a Michael Frayn or a David Lodge to sketch proceedings. They'd have fun, I reckon, with the melee of academics clustered around the great man of American letters, and they'd no doubt throw in a semiotic mishap and a bit of bedroom farce for good measure.

I mean merely to josh, not to be blatantly irreverent, for who would seriously argue that Roth's career is not worthy of celebration? More than 50 years of writing, 27 novels, umpteen essays and stories, books that are one-offs, books that come in series, Zuckerman novels, Kepesh novels, comedies, tragedies, sex, politics, the mind, the body, men, women and possibly the most famous (or infamous) piece of liver ever to appear in fiction? It's not nothing.

But it is, according to Roth, all that there will be. Last year, the writer told a French magazine, Les Inrocks, that he had retired and that Nemesis, which was published in 2010, would be his last novel. His decision sprang from a characteristically rigorous process; he had reread all his books, beginning with the most recent, in order to see if he had wasted his time. Luckily, he reported: "I thought it was more or less a success", adding that he had, like the boxer Joe Louis, done the best with what he'd had. But, finally, he had come to the conclusion that enough was enough.

Roth has lived a life so dedicated to his work – long, isolated days wrestling with tricky, often painful material – that it's hard not to take his valediction at face value; despite the mixed reception received by some of his later novels , his withdrawal is unlikely to have been caused by a fit of pique. Instead, the overall quality of his prodigious output prompts us to trust his belief that his fictional project is complete.

Will we ever see his like again? The 30 writers and critics who were surveyed last month by New York magazine seemed unsure – and equally unsure about what that might actually mean. A heartening 77% of the respondents, who included Bret Easton Ellis, Elif Batuman and Neil LaBute and of whom the most celebrated was surely Salman Rushdie, voted him the greatest living American novelist and a whopping 97% thought he should win the Nobel prize.

Elsewhere, a slightly less complimentary tone creeps in. In response to the question "What is his great subject?", 21% plumped for mortality, two separate lots of 14% for Jewishness and sex, and a mere (but nonetheless baffling) 7% for celebrity – leaving 43% to vote for narcissism.

Of course, given that these were largely writers giving their thoughts, they mightn't have meant that as a criticism. The breakdown to the question "Is Roth a misogynist?", to which 17% replied yes, 30% no and 52% "Well...", is similarly ambiguous (ditto with the maths). And even the one "no" vote for the Nobel prize came only on the grounds of Roth's retirement.

This was all fun, or as much fun as writers actually feel comfortable having. Less so have been the various controversies that have attended Roth. There is the lack of the Nobel, for example, which became identified, five or so years ago, with America's lack of a Nobel in literature, following remarks about insularity made by the then permanent secretary of the Swedish Academy, Horace Engdahl. Then, a rather more direct hit came Carmen Callil's resignation from the judging panel of the International Man Booker prize in the face of its decision to present Roth with the award. Among her objections, what stuck most persistently in the mind was the idea that reading him made one feel "as though he's sitting on your face and you can't breathe".

And now look what's happened. Roth is hardly short of awards, but it's bad luck that he should have chosen to put away his pen just as a new British literary prize heaves into view. The Folio prize – I must straightforwardly disclose that I sit on its advisory committee – is open to all works of fiction written in English and published in the UK; an academy of writers and critics will decide on the majority of its entries and provide its judges. Much has been made of the challenge that it might, or might not, present to the perceived dominance of the Man Booker prize and that rests largely on the question of American writers, who are not eligible for the Booker.

There is, naturally and thankfully, room for more than one prize and for more than one set of entry criteria. But it has often been thought – anecdotally, of course – that we better not let the Americans in or they'll win everything. The Women's Prize for Fiction, formerly the Orange prize, proved that that wasn't the case, with a wonderfully diverse list of winners; its 2013 longlist, published last week, is one of its most intriguing for years.

It's impossible to say whether Roth would have won the Folio prize if he'd still been writing, but he'd have been in with a good shot. Bravo to him for knowing when to call it quits, but bravo, too, to those who keep going. One of this year's most hotly passed around advance copies has been that of an exquisitely written novel, entitled All That is, by the American writer James Salter. He is 87 years old. Now that's stamina.